Zusammenfassung der Ressource
Metabolism and Enzymes
- Cell Metabolism
- collective term for thousands of biochemical reactions
that occur in a living cell
- Metabolic Pathways
- a series of enzyme controlled reactions
- can be reversible/irriversible
- Anabolic reactions
- large molecules are synthesised from
several smaller molecules - energy
required
- Catabolic reactions
- Large molecules are broken down into
smaller molecules - energy released
- Control of Metabolic Pathways
- Gene Expression - genes are switched on and off. inducer binds to
repressor, enzyme activity switched on, when all substrates synthesied,
inducer frees repressor and repressor then switches off gene
- Signal Molecules - can trigger reactions that switch genes
on/off. Inracellular signal molecules work inside the cell that
produced them, Intercellular signal molecules is from outside
the cell that produced them.
- Inhibitors
- Non-Competitive
- Bind to non-active sight and alter the
shape of the active site, permanently
denaturing enzyme
- Effect is permanent
- Competitive
- Similar shape to enzyme active
site, bind to it, and temporarily
block it from binding with substrate
- Effect can be cancelled out
by and increase in substrate
concentration
- End Product (negative feedback) inhibition
- the end product acts as a negative feedback to
the pathway. inhibits and earlier enzyme, stops
wasteful conversions
- Enzymes
- Biological catalysts, speed up reaction by lowering
activation energy and providing and alternative route,
without being used up
- Activation energy is the minimum energy required for bonds to break and
a reaction to take place, enzymes lower this so it can take place in living
cells, below 40.C
- induced fit
- each enzyme can only act on one substrate. the active site is
flexible and can fit perfectly to the substrate